Treatment of gold and silver ores, &amp;c.



'No. 646,006. Patented Mar. 27, 1906.

J. C. MONTGOMEBIE 8:. H. PABKES.

TREATMENT OF GOLD AND SILVER OBES, 6L0. (Application filed my 29, 1897.).(No Model.)

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NITED STATES PATENT Erica.

JOHN OUNINGHAME MONTGOMERIE, OF STAIR, SCOTLAND, AND HENRY PARKES, OFLONDON, ENGLAND.

TREATMENT OF GOLD AND SILVER ORES, 81,0.

SPECIFICATION forming part of Letters Patent No. 646,006, dated March27, 1900. Application filed May 29,1897. Serial No. 638,796. (Nospecimens.)

To all whom it may concern:

Be it known that we, JOHN OUNINGHAME 1 Great Britain and Ireland, haveinvented certain new and useful improved means appli-- cable for use inthe treatment of ores or compounds containing gold or silver and inmeans applicable for use in the treatment of such materials with the aidof solvents, (in respect whereof we have applied for Letters Patent inGreat Britain to bear date April 21, 1897, No. 9,964,) of which thefollowing is a specification. i i

This invention relates to the treatment of auriferous and argentiferousores or com-, pounds for the purpose of separating and collecting thegold and silver contained therein, the objects of the invention being tosecure expedition, a high percentage of extraction, and economy in thecost of Working.

The accompanying drawing illustrates a revolving barrel such as isusually employed in the treatment of ores.

A is the casing, which maybe of cast-iron and be furnished with a woodor earthenware lining B. A lead or other suitable lining O is interposedbetween the casing A and lining B. The barrel is mounted upon rollers orwheels D D, Which work in the tracks a a, formed on the casing, therotation of the bar rel being eifected by means of a toothed pinion (notshown) gearing with the toothed rack or Wheel a on the barrel-casing.

E is the manhole for use in charging and discharging the barrel, thesame being provided with a tight-closing cover E.

F is the inlet for compressed air, furnished with a screw-down valve F.

\Vithin the barrel one or more ribs or breaks G are provided, with aview to assisting in turning the mass during the revolution of thebarrel.

In applying our invention to the treatment of ores containing gold orsilver or gold and silver We crush the ore sufficiently fine to admit ofits passing through a sieve of from forty to sixty meshes to the linealinch. Genmetal oxid or a hydrate of an alkali-metal oxid or of analkali-earth metal, and, third, sodium dioxid or sodiumor potassium orother alkali metal or alkali-earth metal, nitroprussid, bromid, orfluorid, or barium dioxid or-peroxid of lead or other suitableoxygen-yielding substance may be employed in conjunction with ammoniumsulfate or other reagent, operating to liberate oxygen therefrom. Amongthese may be mentioned the alkali-metal salts whose acid radicalcontains bromin, fluorin, phosphorus-such as NaH PO Na HPO .12H O, Na P'O .10H O-carbon-such as Na O O .2H O, Na OO ,1OH O, K C H O -and sulfur, such as Na S O '.7H O, Na SO .10H O, NaHSO In some instancesammonium sul= fate may also with advantage be employed in conjunctionwith the bromid or fluorid. Bromin or fluorin water may, if preferred,be substituted for a bromid or fluorid. The barrel is revolved for ashort time in order to thoroughly mix its contents, and the ore havingbeen added the barrel is then charged through the inlet F with air undera pressure of from fifty to one hundred pounds per square inch. Thevalve F having been screwed down and the airpump disconnected, thebarrel is maintained in rotation until the precious metals are, so faras is practicable, dissolved, the time 0ccupied with average ores beingfrom four to six hours. The barrel is thereupon emptied, after firstremoving the manhole -cover E, the contents filtered and washed, and thesolution treated in any known manner for the separation of the preciousmetals. We

prefer, however, to filter and to proceed as regards the reuse of theliquor in the manner set forth in the specification to Letters Patentgranted to John Ouninghame Montgomerie, No. 524,601, dated August 14,1894, and No. 532,895, dated January 22, 1895, and as regards therecovery of the precious metals from the solution in the mannerdescribed in the specification to Letters Patent No. 549,7 36, datedNovember 12, 1895.

The treatment above referred to may also be carried out in tanks withoutair-pressure or agitation. Under such circumstances it is preferable toallow the solvent liquid to percolate through the mass of orerepeatedly, the liquid as it passes away being fed back to the surfaceof the ore until the precious metals are sufliciently dissolved.

By way of example, a free-milling or ordinary refractory ore containingforty ounces, six pennyweights, and one grain of gold and one ounce, sixpennyweights, and three grains of silver per ton may be treated withfourteen pounds of cyanid of potassium, ten pounds of caustic soda, fivepounds of red lead, and four pounds of bromid or of sulfate of ammonia.These proportions willbe subject to considerable variation withdifferent descriptions of ore and according to the particular chemicalagents selected, the most suitable proportions being, however, readilydeterminable by experiment. Inasmuch as a very small proportion of thechemicals, such as the cyanid and caustic soda, is consumed during thetreatment of the first quantity of ore, the requisite quantity ofchemicals necessary for the further strengthening of the solution onreuse in order to bring it up to its orginal strength can only bedetermined on testing the liquid subsequently to the treatment of asecond quantity of ore. In any case the chemical agents mentioned underthe third head must be added to each charge of ore as their chemicalaction becomes exhausted with each charge of ore. \Vith ores or tailingsoperated on by the tank method of treatment weak solutions of cyanid andcaustic alkali are generally used and the time allowed to complete thedissolution of the precious metals extended considerably, the rate ofextraction being much slower. When an insoluble salt is used in tanktreatment without agitation, it may be mixed with the ore or spread uponthe top of it or arranged in layers throughout the ore.

What We claim as our invention, and desire to secure by Letters Patent,is-

In the extraction of gold and silver from ores or compounds containingthe same, the herein-described process consisting in treating the ore orcompound with a cyanid of an alkali metal, caustic alkali and bariumdi-' 'oxid in conjunction with ammonium sulfate substantially as setforth.

JOHN CUNINGIIAME DIONJGOMPIRH]. HENRY PARKES.

Witnesses:

F. J. RAPSON, W. F. CAIN

